Fluoroelastomers such as vinylidene fluoride/hexafluoropropylene and tetrafluoroethylene/propylene copolymers are vulcanized by adding to them a vulcanizing agent followed by heating or by irradiating the fluoroelastomers as such. The thus vulcanized fluoroelastomers have excellent properties such as heat resistance and chemical resistance.
The conventional vulcanizable fluoroelastomer compositions, however, have inferior processability, particularly mold releasability and mold contamination proofness, to those of common non-fluoroelastomers. Especially, the fluoroelastomer composition containing a peroxide vulcanizing agent has worse mold releasability than those containing other vulcanizing agents.